Power factor

ABSTRACT

A method for improving power factor includes collecting consumption data of at least one appliance, building a consumption profile for each of the at least one appliance based on the consumption data collected, reconstructing reactive power consumption of each of the at least one appliance based on the consumption profile for each of the at least one appliance, and computing a schedule for each of the at least one appliance in accordance the reactive power consumption of each of the at least one appliance to improve power factor while respecting at least one constraint.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/433,653, filed Mar. 29, 2012, and incorporated by reference herein.

FIELD OF THE INVENTION

Embodiments of the invention generally relate to information technology,and, more particularly, to power factor technology.

BACKGROUND

Power factor (PF) is a measure of electrical efficiency and is given bythe ratio of kilo-watt (KW) to kilo-volt-ampere (KVA). KW is actualpower consumed by a load whereas KVA is total power delivered to theload. The power consumed is referred to as active power and theremaining is referred to as re-active power, and only the active powerdoes the actual work. However, even though reactive power does notperform any actual work, it still needs to be generated and carried.

Power factor varies between 0 (least efficient) and 1 (most efficient).When PF<1, KVA travels through the wires between the load and theutility grid, passing back and forth through, for example, a residentialmeter. Disadvantages of low power factor include, by way of example,substantially higher monthly electricity bills if reactive power ischarged, large capacity payments for providing reactive power, andreduction of the lifetime of devices.

Improving the power factor is referred to as Power Factor Correction(PFC). Historically, PFC has been achieved through specialized,expensive and difficult-to-maintain hardware at the distribution orconsumption site. However, existing approaches such as capacitor bankshave a number of disadvantages. For example, capacitors are large, sothe cost of plant real estate must be included in economicconsiderations. Additionally, capacitor banks can provide reactive powerbut they cannot absorb it, and capacitor banks typically have a life ofless than ten years, thereby requiring repeated capital investments.

SUMMARY

In one aspect of the present invention, techniques for improving powerfactor are provided. An exemplary computer-implemented method forimproving power factor can include steps of collecting consumption dataof at least one appliance, building a consumption profile for each ofthe at least one appliance based on the consumption data collected,reconstructing reactive power consumption of each of the at least oneappliance based on the consumption profile for each of the at least oneappliance, and computing a schedule for each of the at least oneappliance in accordance the reactive power consumption of each of the atleast one appliance to improve power factor while respecting at leastone constraint.

Another aspect of the invention or elements thereof can be implementedin the form of an article of manufacture tangibly embodying computerreadable instructions which, when implemented, cause a computer to carryout a plurality of method steps, as described herein. Furthermore,another aspect of the invention or elements thereof can be implementedin the form of an apparatus including a memory and at least oneprocessor that is coupled to the memory and operative to perform notedmethod steps. Yet further, another aspect of the invention or elementsthereof can be implemented in the form of means for carrying out themethod steps described herein, or elements thereof; the means caninclude (i) hardware module(s), (ii) software module(s), or (iii) acombination of hardware and software modules; any of (i)-(iii) implementthe specific techniques set forth herein, and the software modules arestored in a tangible computer-readable storage medium (or multiple suchmedia).

These and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating power travelling without scheduling;

FIG. 2 is a diagram illustrating power travelling with scheduling,according to an embodiment of the present invention;

FIG. 3 is a block diagram illustrating an example embodiment, accordingto an aspect of the invention;

FIG. 4 is a diagram illustrating operational modality, according to anembodiment of the present invention;

FIG. 5 is a diagram illustrating an example circuit design to minimizecirculating reactive power, according to an embodiment of the presentinvention;

FIG. 6 is a flow diagram illustrating techniques for improving powerfactor, according to an embodiment of the invention; and

FIG. 7 is a system diagram of an exemplary computer system on which atleast one embodiment of the invention can be implemented.

DETAILED DESCRIPTION

As described herein, an aspect of the present invention includesdecentralized power factor correction via intelligent load scheduling.As also described herein, an example embodiment of the inventionprovides a saving in electricity bills by reducing reactive power drawnfrom grid, a reduction in distribution system losses by improving powerfactor, as well as an improved voltage profile by reducing back andforth reactive power flow within grid and load.

In at least one embodiment of the invention, capacitive loads (such aslight-emitting diode (LED) lights and electronics) can be scheduled tobe run at the same time as highly inductive loads (such as washingmachines, etc.). The net power factor at the mains/meter will by muchcloser to 1, and the capacitive loads can essentially provide reactivepower for the inductive loads. Also, in accordance with at least oneembodiment of the invention, because the schedules are software only, noextra hardware (for example, a capacitor bank, switching circuits, etc.)is required.

As described herein, a framework for improving the power factor, forexample, at a residence, includes taking into account customer specificpreferences and needs, as well as other factors such as availablesources of power including but not limited to solar power, wind power,local generation, and other renewable sources. In an example embodimentof the invention, a circuit can be designed and implemented such thatthe electrical distance between inductive and capacitive loads isreduced to reduce the power losses (due to back and forth reactive powerflow).

An aspect of the invention includes considering the location ofnon-critical and critical loads (for example, in the same home orbuilding), including distance reduction loss due to a power factor lessthan 1. User preferences can be created through analysis of historicaldata or through explicit user input in a consumption profiler. Further,user preferences are considered in the compared work. For example, thenon-critical can be used if plugged-in or not used if not plugged-in.Devices can be scheduled or re-scheduled, and schedulable loads such asdishwashers and washing machines are neither critical nor non-criticalbecause they are deferrable but have deadlines.

Accordingly, an aspect of the invention includes collecting and buildinguser preferences, and using the preferences to understand when best toschedule and reschedule loads to improve power factor. Improving powerfactor at a residence, for example, prevents reactive power fromoscillating from the generator to load requiring larger capacity buildup.

FIG. 1 is a diagram illustrating power travelling without scheduling. Byway of illustration, FIG. 1 depicts an electric grid 102 that providesactive power (thin grey line) and reactive power (thicker black line).FIG. 1 also depicts an inductive load 104, a resistive load 106 and acapacitive load 108. As illustrated in FIG. 1, without scheduling, thereactive power travels between the grid 102 and the inductive load 104.

In every cycle of alternating current, inductive load 104/capacitiveload 108 stores a part of the supplied energy as a magneticfield/electric field during half of the cycle and stored energy returnsto the source in the remaining half-cycle. Hence, if the loads operateindividually, the source needs to supply this circulating energy.Fortunately, when capacitor loads are charged, inductive loads aredischarged and vice versa. Accordingly, while they operate together, inone half-cycle, capacitive load 108 supplies reactive power to theinductive load 104 and in the other half-cycle, inductor load 104 sendsback the stored energy to the capacitor load 108. Thus, stored energycirculates within the inductive and capacitive loads that minimize thelong distance circulating power between source and load.

Additionally, when loads draw the circulating reactive power fromsource, a significant portion of this power is lost (as I²R loss where Iis current and R is resistance of the wire) when travelling through longdistance transmission lines. If reactive power circulates locally withininductive and capacitive loads, it reduces transmission losssignificantly and also relieves some capacity on the transmission line.

FIG. 2 is a diagram illustrating power travelling with scheduling,according to an embodiment of the present invention. By way ofillustration, FIG. 2 depicts an electric grid 112 that provides activepower (thin grey line) and reactive power (thicker black line). FIG. 2also depicts an inductive load 114, a resistive load 116 and acapacitive load 118. As illustrated in FIG. 2, with scheduling, thereactive power travels within loads.

FIG. 3 is a block diagram illustrating an example embodiment, accordingto an aspect of the invention. FIG. 3 depicts a grid 302 as well as aresidential or commercial location 304. Further, as depicted in FIG. 3,a PFC system of an example embodiment of the invention includes a smartmeter 306, a consumption analyzer/profiler module 308 and a schedulermodule 310.

The smart meter 306 measures active and reactive power consumption ofappliances. A smart meter can already be installed at many homes due tosmart grid initiatives, or can be installed at a device-level or amain-level or both. The consumption profiler software module 308 can berun on data collected from the smart meter 306, and can collect andupdate consumption profiles of appliances. Further, the consumptionprofiler module 308 reconstructs active and reactive power consumptionof each appliance. An embodiment of the invention can either utilizeplug-level meters (where available) or non-intrusive Appliance LoadMetering (NIALM) along with a database of device characteristics toreconstruct appliance consumption profiles.

The scheduler software module 310, which can be installed at home,industry or commercial locations, stores and processes consumptionhistory and appliance profiles. Additionally, the scheduler module 310computes schedules for appliances to improve power factor whilerespecting external constraints (such as user availability, comfort,etc.). As depicted in FIG. 3, the scheduler module displays the scheduleto each customer in step 312, and can also edit the schedule (ifrequired) in step 314.

FIG. 4 is a diagram illustrating operational modality, according to anembodiment of the present invention. By way of illustration, FIG. 4depicts an electric grid 402, a smart energy meter 404, a consumptionprofiler module 406 and a scheduler module 414. As also depicted in FIG.4, the electric grid 402 provides electricity which is measured by theenergy smart meter 404, which thereby provides input to the consumptionprofiler module 406. Therein, step 408 includes collecting a consumptionprofile and usage patterns. Step 410 includes analyzing and building aconsumption profile of each appliance based on a knowledgebase.Additionally step 412 includes analyzing reactive power consumption ofeach appliance.

The consumption profiler module 406 accordingly provides input to thescheduler module 414. The scheduler module 414 includes a plannercomponent 416, which displays the plan in step 418. Also, user input 420can cause the scheduler module 414 to edit the plan in step 422.Ultimately, the final plan 424 is generated.

An aspect of the invention includes classifying the consumption patternsof loads as resistive, inductive or capacitive. Additionally, theinductive and capacitive appliances are scheduled in such a way thatreactive power travels within the group of inductive and capacitiveappliances, reducing back and forth movement of reactive power withinappliances and the grid. In accordance with at least one embodiment ofthe invention, this is achieved by minimizing following cost function:

${g = {E + {\sum\limits_{j = 1}^{d^{\prime}}\left\lbrack {\in_{1}{{*I_{1}^{j}} +} \in_{2}{*I_{2}^{j}}} \right\rbrack}}};$${{\sum\limits_{j = 1}^{d^{\prime}}L_{j}} \leq S_{c}};$${E = {\sum\limits_{t = 1}^{k}{\left( {\sum\limits_{j = 1}^{d^{\prime}}y_{jt}} \right) \times R_{t}}}},$where E is a cost for consuming reactive power, y is the level ofreactive power consumption which is a function the power factor, R isthe rate for reactive power, d′ is the number of appliances, ε is aweight factor, I₁ and I₂ are measures of the user inconvenience when theoperating level and operating time (respectively) of the device aremodified to improve power factor, L_(j) is power consumed by load andS_(c) is source power capacity.

By way of illustration, an example embodiment of the invention caninclude obtaining load characteristics such as power profile over time,and power factor profile over time for different appliance at alocation. Accordingly, an aspect of the invention can then include usinga combinatorial optimization to co-schedule devices, shift or rescheduledevices and schedule power sources to trade-off overall power factor andcustomer utility. A combinatorial solution algorithm can search throughall or a large portion of the space of possible solutions that satisfythe constraints in order to find a schedule that maximizes objectivefunction value. Optimal algorithms can include (but are not limited to)search algorithms such as breadth first or depth first search ofpossible schedules. In at least one embodiment of the invention,intelligent elimination of infeasible or low objective value solutionscan also be incorporated to improve computational efficiency.

An aspect of the invention can also include using sub-optimal convexapproximations to the overall power factor, utility and constraints togenerate a formulation which can be solved optimally. Further, anotheraspect of the invention can include using sub-optimal non-convexapproximations followed by sub-optimal heuristics to schedule the loads.When the number of appliances is large, (sub-optimal) approximations canbe used to schedule devices using various heuristics. Heuristics reducethe computational cost at the cost of possible sub-optimality of theobjective function value. Heuristics can include but are not limited tobranch and bound algorithms, A* search and genetic algorithms. Suchheuristics intelligently eliminate or postpone the evaluation of largesets of unlikely solutions.

By way of example, if capacitive and inductive loads are scheduled torun at the same time, the net power factor can be increased, resultingin improved power factor without special hardware. Additionally, atleast one embodiment of the invention includes a circuit design tominimize distance between scheduled inductive and capacitive loads.

FIG. 5 is a diagram illustrating an example circuit design to minimizecirculating reactive power, according to an embodiment of the presentinvention. By way of illustration, FIG. 5 depicts a main power line 502,inductive load 504, capacitive load 506, resistive component 508,inductive load 510 and capacitive load 512. FIG. 5 displays a circuitdesign where inductive and capacitive loads are connected close to eachother, thereby minimizing the reactive power circulation path betweeninductive and capacitive loads. This reduces power loss behind themeter. For example, if the locations of loads 506 and 510 areinterchanged, reactive power has to travel a longer distance as thegroup of inductive loads is farther from the group of capacitive loads.This would increase the loss on the line while transmitting power.

FIG. 6 is a flow diagram illustrating techniques for improving powerfactor, according to an embodiment of the present invention. Aspects ofthe invention can be carried out, for example, both automatically andvia manual implementation. Step 602 includes collecting consumption dataof at least one appliance. This step can be carried out, for example,using a consumption profiler module. Collecting consumption data of atleast one appliance can include collecting consumption data from a smartmeter. Also, the at least one appliance can be a component of aresidence, a group of residences or a commercial location.

Step 604 includes building a consumption profile for each of the atleast one appliance based on the consumption data collected. This stepcan be carried out, for example, using a consumption profiler module.Step 606 includes reconstructing reactive power consumption of each ofthe at least one appliance based on the consumption profile for each ofthe at least one appliance. This step can be carried out, for example,using a consumption profiler module.

Step 608 includes computing a schedule for each of the at least oneappliance in accordance the reactive power consumption of each of the atleast one appliance to improve power factor while respecting at leastone constraint. This step can be carried out, for example, using ascheduler module. Constraints can include, by way of example, useravailability, comfort, user preference for device usage time andduration and delay, user preference for device usage intensity andchange in intensity, user preference for device co-scheduling andre-scheduling, cost related to reactive power, and available source ofpower. Available sources of power can include, but are not limited to,solar power, wind power, local generation, and other renewable sourceswhich have different active and reactive power costs andcharacteristics.

Computing a schedule for each of the at least one appliance can includeco-scheduling multiple appliances to improve a net power factor. Also,computing a schedule for each of the at least one appliance can includere-scheduling an appliance based on real-time pricing of reactive power.

The techniques depicted in FIG. 6 can also include storing theconsumption profile for each of the at least one appliance in adatabase. Additionally, as described herein, an embodiment of theinvention can include displaying the schedule via an output device, aswell as editing the schedule based on user input. Further, theconsumption profile of an appliance can be updated. As also detailedherein, the techniques depicted in FIG. 6 can include implementing acircuit so as to reduce electrical distance between inductive andcapacitive loads so that power loss is reduced.

The techniques depicted in FIG. 6 can also, as described herein, includeproviding a system, wherein the system includes distinct softwaremodules, each of the distinct software modules being embodied on atangible computer-readable recordable storage medium. All the modules(or any subset thereof) can be on the same medium, or each can be on adifferent medium, for example. The modules can include any or all of thecomponents shown in the figures. In an aspect of the invention, themodules include a consumption profiler module and a scheduler modulethat can run, for example on a hardware processor. The method steps canthen be carried out using the distinct software modules of the system,as described above, executing on a hardware processor. Further, acomputer program product can include a tangible computer-readablerecordable storage medium with code adapted to be executed to carry outat least one method step described herein, including the provision ofthe system with the distinct software modules.

Additionally, the techniques depicted in FIG. 6 can be implemented via acomputer program product that can include computer useable program codethat is stored in a computer readable storage medium in a dataprocessing system, and wherein the computer useable program code wasdownloaded over a network from a remote data processing system. Also, inan aspect of the invention, the computer program product can includecomputer useable program code that is stored in a computer readablestorage medium in a server data processing system, and wherein thecomputer useable program code are downloaded over a network to a remotedata processing system for use in a computer readable storage mediumwith the remote system.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in a computer readable medium havingcomputer readable program code embodied thereon.

An aspect of the invention or elements thereof can be implemented in theform of an apparatus including a memory and at least one processor thatis coupled to the memory and operative to perform exemplary methodsteps.

Additionally, an aspect of the present invention can make use ofsoftware running on a general purpose computer or workstation. Withreference to FIG. 7, such an implementation might employ, for example, aprocessor 702, a memory 704, and an input/output interface formed, forexample, by a display 706 and a keyboard 708. The term “processor” asused herein is intended to include any processing device, such as, forexample, one that includes a CPU (central processing unit) and/or otherforms of processing circuitry. Further, the term “processor” may referto more than one individual processor. The term “memory” is intended toinclude memory associated with a processor or CPU, such as, for example,RAM (random access memory), ROM (read only memory), a fixed memorydevice (for example, hard drive), a removable memory device (forexample, diskette), a flash memory and the like. In addition, the phrase“input/output interface” as used herein, is intended to include, forexample, a mechanism for inputting data to the processing unit (forexample, mouse), and a mechanism for providing results associated withthe processing unit (for example, printer). The processor 702, memory704, and input/output interface such as display 706 and keyboard 708 canbe interconnected, for example, via bus 710 as part of a data processingunit 712. Suitable interconnections, for example via bus 710, can alsobe provided to a network interface 714, such as a network card, whichcan be provided to interface with a computer network, and to a mediainterface 716, such as a diskette or CD-ROM drive, which can be providedto interface with media 718.

Accordingly, computer software including instructions or code forperforming the methodologies of the invention, as described herein, maybe stored in an associated memory devices (for example, ROM, fixed orremovable memory) and, when ready to be utilized, loaded in part or inwhole (for example, into RAM) and implemented by a CPU. Such softwarecould include, but is not limited to, firmware, resident software,microcode, and the like.

A data processing system suitable for storing and/or executing programcode will include at least one processor 702 coupled directly orindirectly to memory elements 704 through a system bus 710. The memoryelements can include local memory employed during actual implementationof the program code, bulk storage, and cache memories which providetemporary storage of at least some program code in order to reduce thenumber of times code must be retrieved from bulk storage duringimplementation.

Input/output or I/O devices (including but not limited to keyboards 708,displays 706, pointing devices, and the like) can be coupled to thesystem either directly (such as via bus 710) or through intervening I/Ocontrollers (omitted for clarity).

Network adapters such as network interface 714 may also be coupled tothe system to enable the data processing system to become coupled toother data processing systems or remote printers or storage devicesthrough intervening private or public networks. Modems, cable modem andEthernet cards are just a few of the currently available types ofnetwork adapters.

As used herein, including the claims, a “server” includes a physicaldata processing system (for example, system 712 as shown in FIG. 7)running a server program. It will be understood that such a physicalserver may or may not include a display and keyboard.

As noted, aspects of the present invention may take the form of acomputer program product embodied in a computer readable medium havingcomputer readable program code embodied thereon. Also, any combinationof one or more computer readable medium(s) may be utilized. The computerreadable medium may be a computer readable signal medium or a computerreadable storage medium. A computer readable storage medium may be, forexample, but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, ordevice, or any suitable combination of the foregoing. More specificexamples (a non-exhaustive list) of the computer readable storage mediumwould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random access memory(RAM), a read-only memory (ROM), an erasable programmable read-onlymemory (EPROM or Flash memory), an optical fiber, a portable compactdisc read-only memory (CD-ROM), an optical storage device, a magneticstorage device, or any suitable combination of the foregoing. In thecontext of this document, a computer readable storage medium may be anytangible medium that can contain, or store a program for use by or inconnection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing an appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of at least oneprogramming language, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. Accordingly, an aspect of the inventionincludes an article of manufacture tangibly embodying computer readableinstructions which, when implemented, cause a computer to carry out aplurality of method steps as described herein.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, component, segment,or portion of code, which comprises at least one executable instructionfor implementing the specified logical function(s). It should also benoted that, in some alternative implementations, the functions noted inthe block may occur out of the order noted in the figures. For example,two blocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

It should be noted that any of the methods described herein can includean additional step of providing a system comprising distinct softwaremodules embodied on a computer readable storage medium; the modules caninclude, for example, any or all of the components detailed herein. Themethod steps can then be carried out using the distinct software modulesand/or sub-modules of the system, as described above, executing on ahardware processor 702. Further, a computer program product can includea computer-readable storage medium with code adapted to be implementedto carry out at least one method step described herein, including theprovision of the system with the distinct software modules.

In any case, it should be understood that the components illustratedherein may be implemented in various forms of hardware, software, orcombinations thereof; for example, application specific integratedcircuit(s) (ASICS), functional circuitry, an appropriately programmedgeneral purpose digital computer with associated memory, and the like.Given the teachings of the invention provided herein, one of ordinaryskill in the related art will be able to contemplate otherimplementations of the components of the invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition ofanother feature, integer, step, operation, element, component, and/orgroup thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

At least one aspect of the present invention may provide a beneficialeffect such as, for example, improving a voltage profile by reducingback and forth reactive power flow within grid and load.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

What is claimed is:
 1. A computer-implemented method for improving powerfactor, wherein the computer-implemented method comprises: collectingconsumption data of at least one inductive appliance and at least onecapacitive appliance; building a consumption profile for each of the atleast one inductive appliance and the at least one capacitive appliancebased on the consumption data collected; reconstructing reactive powerconsumption of each of the at least one inductive appliance and the atleast one capacitive appliance based on the consumption profile for eachof the at least one inductive appliance and the at least one capacitiveappliance, wherein said reactive power is distinct from active power,said reactive power being stored in an appliance and said active powerbeing consumed by the appliance; and computing a single operatingschedule encompassing the at least one inductive appliance and the atleast one capacitive appliance, in accordance with the reconstructedreactive power consumption, to reduce reactive power flow within the atleast one inductive appliance and the at least one capacitive applianceto improve power factor while respecting at least one constraint;wherein the steps are carried out by instructions that are (i) embodiedon at least one non-transitory computer readable storage medium and (ii)executable by at least one computer device.
 2. The computer-implementedmethod of claim 1, further comprising: storing the consumption profilefor each of the at least one inductive appliance and the at least onecapacitive appliance in a database.
 3. The computer-implemented methodof claim 1, further comprising: displaying the operating schedule via anoutput device.
 4. The computer-implemented method of claim 1, furthercomprising: editing the operating schedule based on user input.
 5. Thecomputer-implemented method of claim 1, wherein collecting consumptiondata of the at least one inductive appliance and the at least onecapacitive appliance comprises collecting consumption data from a smartmeter.
 6. The computer-implemented method of claim 1, furthercomprising: updating the consumption profile of at least one of the atleast one inductive appliance and the at least one capacitive appliance.7. The non-transitory computer-implemented method of claim 1, whereinthe at least one constraint comprises at least one of user availability,comfort, user preference for device usage time and duration and delay,user preference for device usage intensity and change in intensity, userpreference for device co-scheduling and re-scheduling, cost related toreactive power, and available source of power.
 8. Thecomputer-implemented method of claim 1, wherein the at least oneinductive appliance is a component of a residence, a group of residencesor a commercial location.
 9. The computer-implemented method of claim 1,wherein said computing the operating schedule comprises co-schedulingmultiple appliances to improve a net power factor.
 10. Thecomputer-implemented method of claim 1, wherein said computing theoperating schedule comprises re-scheduling an appliance based onreal-time pricing of reactive power.
 11. The computer-implemented methodof claim 1, further comprising: implementing a circuit so as to reduceelectrical distance between inductive and capacitive loads so that powerloss is reduced.
 12. A computer-implemented method comprising:classifying, from a collection of multiple appliances, one or moreinductive appliances and one or more capacitive appliances; computingone or more reactive power parameters pertaining to the one or moreinductive appliances and the one or more capacitive appliances; andscheduling the one or more inductive appliances and the one or morecapacitive appliances together via a single operating schedule toshorten flow of the reactive power within the one or more inductiveappliances and the one or more capacitive appliances by minimizing acost function, wherein said cost function is based on at least (i) acost for consuming reactive power, (ii) a level of reactive powerconsumption by the one or more inductive appliances and the one or morecapacitive appliances, (iii) a rate for reactive power, and (iv) thenumber of appliances among the one or more inductive appliances and theone or more capacitive appliances: wherein the steps are carried out byinstructions that are (i) embodied on at least one non-transitorycomputer readable storage medium and (ii) executable by at least onecomputer device.
 13. The computer-implemented method of claim 12,wherein the cost function is further based on source power capacity. 14.The computer-implemented method of claim 12, wherein the cost functionis further based on measures of user inconvenience when an operatinglevel and an operating time, respectively, of a given appliance aremodified.
 15. The non-transitory computer-implemented method of claim12, wherein the cost function is further based on power consumed by aload associated with the one or more inductive appliances and the one ormore capacitive appliances.